Power semiconductor module

ABSTRACT

The invention relates to a power semiconductor module having at least one power semiconductor switch, a cooling system, control electronics and a relieving network. According to this invention, these components are cast with an insulating medium to form a solid block, with the connections of the power semiconductor switch, the control equipment and the cooling system projecting out of the block. This yields a compact power semiconductor module which can be installed in an outdoor framework structure and is encapsulated to insulate it against environmental influences.

FIELD OF THE INVENTION

The present invention is directed to a power semiconductor module havingat least one power semiconductor switch, a cooling system, controlelectronics, and a relieving network.

BACKGROUND INFORMATION

In high-voltage applications in power electronics, such as high-voltaged.c. transmission (HVDCT), static var compensation (SVC), andhigh-voltage variable-speed drives, a plurality of power semiconductorswith their cooling systems, control electronics, and relieving networksare usually connected electrically in series to achieve adequatedielectric strength. The combination of power semiconductors and theirassociated cooling systems, control electronics, and relieving networksis known as a thyristor station. A plurality of such thyristor stationsare combined mechanically in one module, and the design of the modulemust meet certain mechanical requirements and other requirementsregarding the electric insulation of the components.

Such a module is described in the journal IEEE Transactions on PowerApparatus and Systems, vol. PAS-94, no. 3, May/June 1975, pages1061-1071, and from the two embodiments of low and high direct voltagediscussed in the Siemens brochure "High-voltage direct-currenttransmission (HVDCT)," order no. E50001-U131-A35, imprint PA 3942.

The article cited above concerns a high-voltage direct-currenttransmission system (HVDCT system) whose valves of one phase arearranged in an oil tank. These oil tanks are set up outdoors. Each valvecomprises up to twenty power semiconductor modules. Also described are arelieving network, a block diagram of a control circuit, and the tankarrangement. The tank with its oil filling assumes the function ofelectrically insulating the thyristor stations with respect to themechanical construction of the modules and the entire valve, andshielding all components from environmental influences.

In the conference contribution with the title "State-of-the-ArtThyristor Valves for China's First HVDC Transmission System" of theIEEE/CSEE Joint Conference on High Voltage Transmission Systems inChina, Beijing, Oct. 17-22, 1987, pages 520-528, a high-voltagedirect-current transmission system is proposed using water-cooled valvesthat are accommodated by suspension in a structure. This conferencecontribution describes the design of a modular unit. In addition, thecontrol electronics of a power semiconductor and the valve-baseelectronics for optical transmission of control pulses are described.

The Siemens brochure "Advanced Series Compensation," order no.E50001-U132-A22-X-7600, imprint PA 1932, describes another embodiment ofan arrangement of power semiconductor modules in which the modulesswitch capacitors and are arranged in a special walk-in container on aninsulated platform together with the capacitors and reactance coils of aseries reactive-power compensation system.

Certain technical problems stem from the electrical insulation ofthyristor stations. These problems arise when several thyristor stationsare connected electrically in series to achieve a high dielectricstrength. Additional technical problems also arise with respect tomeasures intended to protect against environmental influences. In thesemeasures, converters are arranged in framework structures and areaccommodated with air insulation in a special structure, container orcabinet, or they are arranged in tanks filled with air or an insulatingliquid. These embodiments have the disadvantage that relativelyexpensive structures are required even for low-power converters, andthese often require complicated approval proceedings. Another problem isthat the tank that is filled with insulating fluid or gas must be openedto replace individual defective components. Such replacement operationscan be very labor-intensive.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved thyristorstation that overcomes in a cost-efficient manner the aforementioneddisadvantages of known thyristor stations.

In particular, this object is achieved by using components that are castwith an insulating medium to form a solid block, with the connections ofthe power semiconductor, the control electronics, and the cooling systemprojecting out of the block. By manufacturing thyristor stations in thismanner, it is now possible to arrange and wire their modular blocks inan outdoor framework structure or to allocate them directly toindividual capacitor banks when capacitors are connected. Thiseliminates the need for a building or container or cabinet or tank. Ifthere are defects in individual components of a modular block, thismodular block is replaced.

When light pulse firing power semiconductors are directly used as powersemiconductors, the advantages of the present invention become apparentbecause the need to use control electronics with numerous electroniccomponents is eliminated. This in turn reduces the probability offailure while at the same time yielding modules that are especiallycompact.

Another advantage of the power semiconductor module according to thepresent invention is that the need to incorporate special measures forair pollution abatement, which are required with today's air-insulateddesigns, is eliminated. The insulating casting compound encapsulates thecomponents of the power semiconductor module, isolating it from theenvironment, so that there is no contamination of the components whichwould be responsible for corona effects or partial discharge andelectric sparkovers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of a power semiconductor module accordingto the present invention.

FIG. 2 is a simplified diagram of a power semiconductor valve module.

DETAILED DESCRIPTION

As shown in FIG. 1, power semiconductor module 2 contains at least onepower semiconductor switch 4, e.g., a thyristor. Accompanying powersemiconductor switch 4 are control electronics 6, which are alsoreferred to as thyristor electronics, a cooling system 8, and arelieving network 10. Thyristor electronics 6 and relieving network 10may correspond, for example, to any suitable thyristor electronics orrelieving networks, such as those discussed in the above-mentionedreferences. Cooling system 8 may comprise, for example, at least onecooling case, a clamping fixture, and several coolant lines. Thesecomponents 4, 6, 8, and 10 of the power semiconductor module 2 arelinked electrically and mechanically. This component set is cast with aninsulating medium 12 to form a solid block 14. The following connectionsextend out of this cast block 14: power supply terminals 16, 18, gateterminals 20, 22, and coolant connections 24, 26. Components 4, 6, 8 and10 of the power semiconductor module 2 are encapsulated and isolatedfrom the environment by the casting compound, so that components 4, 6, 8and 10 are no longer exposed to environmental influences. Plastic, forexample, may be used as the insulating medium 12, and epoxy resinimparts the required rigidity to the block.

A plurality of the power semiconductor modules 2 according to FIG. 1,each of which can be referred to as a thyristor station, are combined toform one power semiconductor valve module 28, as shown in FIG. 2. Thepower semiconductor valve module 28 is also referred to as a valvesection. In addition to thyristor stations 2, the valve section 28includes a saturable valve reactor 30 and a capacitor 32. Thyristorstations 2 and saturable valve reactor 30 are connected electrically inseries, whereas capacitor 32 is connected electrically in parallel withthis series connection. At least one such valve module 28 is used for avalve of a multipulse converter, for example.

This embodiment of the power semiconductor module 2 of the presentinvention allows them to be placed in an outdoor framework structure andconnected electrically to one another according to a wiring diagram of aconverter. This converter design thus resembles that of a capacitor bankwhere the capacitors are inserted into an outdoor framework structure.As a result, it is not necessary to have a special building, valve bayor vessel, so converters of a lower power level in particular are muchless expensive.

If, instead of power semiconductor switch 4, a directly light pulsefiring power semiconductor is used, this eliminates thyristorelectronics 6. As a consequence, the amount of electronic components inthe system is reduced. The use of a directly light pulse firing powersemiconductor thus results in a module 2 that is even more compact andinexpensive.

The power semiconductor module 2 according to the present invention canalso be used with a high-voltage capacitor bank comprising a pluralityof capacitors. These capacitors are arranged in an outdoor frameworkstructure. A power semiconductor module 2 can be connected electricallyin parallel with these capacitors and/or several capacitors may beconnected in series. These power semiconductor modules 2 are alsoarranged in an outdoor framework structure. This yields a compact,variable high-voltage capacitor bank. Instead of capacitors, reactorunits of a reactor unit can also be combined with power semiconductormodules 2, if a compact variable reactor arrangement is needed. Sincemodules 2 can be arranged in an outdoor framework structure, whatresults is a compact embodiment of a high-voltage capacitor bank orreactor arrangement.

What is claimed is:
 1. A power semiconductor module comprising:arelieving network; at least one power semiconductor switch having afirst supply terminal and a second supply terminal; a controlelectronics device coupled to the power semiconductor switch and havinga first gate terminal and a second gate terminal; and a cooling systemcoupled to the control electronics device and having a first coolantconnection and a second coolant connection, wherein the relievingnetwork, the power semiconductor switch, the control electronics device,and the cooling system are cast within an insulating medium forming asolid block, and wherein the first and second supply terminals, thefirst and second gate terminals, and the first and second coolantconnections project out from the block.
 2. The power semiconductormodule according to claim 1, wherein the insulating medium comprisesplastic.
 3. The power semiconductor module according to claim 2, whereinthe plastic comprises an epoxy resin.
 4. The power semiconductor moduleaccording to claim 1, wherein the cooling system comprises at least onecooling case, a clamping fixture, and at least one coolant line.
 5. Thepower semiconductor module according to claim 1, wherein the powersemiconductor switch is activated electrically.
 6. The powersemiconductor module according to claim 1, wherein the powersemiconductor switch is activated by a series of light pulses.
 7. Thepower semiconductor module according to claim 1, wherein the powersemiconductor switch is an interruptible power semiconductor switch. 8.A power semiconductor valve module, comprising:at least one powersemiconductor module, wherein the power semiconductor module comprises:arelieving network; at least one power semiconductor switch having afirst supply terminal and a second supply terminal, a controlelectronics device coupled to the power semiconductor switch and havinga first gate terminal and a second gate terminal, and a cooling systemcoupled to the control electronics device and having a first coolantconnection and a second coolant connection,wherein the relievingnetwork, the power semiconductor switch, the control electronics device,and the cooling system are cast within an insulating medium forming asolid block, and wherein the first and second supply terminals, thefirst and second gate terminals, and the first and second coolantconnections project out from the block; a nonlinear valve reactorforming a series connection with the power semiconductor module; and acapacitor connected in parallel with the series connection.
 9. The powersemiconductor valve module according to claim 8, wherein the seriesconnection includes at least two power semiconductor modules connectedin series.